Joel Spolsky writes in a recent blog entry:
As I worked through the screens that would be needed to allow either party to initiate the process, I realized that Aardvark would be just as useful, and radically simpler, if the helper was required to start the whole process. Making this change in the spec took an hour or two. If we had made this change in code, it would have added weeks to the schedule. I can’t tell you how strongly I believe in Big Design Up Front, which the proponents of Extreme Programming consider anathema. I have consistently saved time and made better products by using BDUF and I’m proud to use it, no matter what the XP fanatics claim. They’re just wrong on this point and I can’t be any clearer than that.
Joel has an interesting perspective on this subject and has written quite eloquently on this and other topics (I highly recommend his books and blog). However, I think he’s just wrong about this. He has a skewed view on software development, having worked at product companies his whole career. Building products is a lot different from building business applications (which is where my experience lies). First, for products, the requirements and design are pretty much made up of a few people’s vision on what the product needs to do. The market place determines if they were right or not. Second, you generally have to do this in secret, especially if you have competitors who will cherry pick your design. Third, you are pretty much required to do a “big bang” deployment, when you ship to customers.
Most business applications aren’t like this. The requirements are very fluid (quite often, the business stakeholders don’t know what they want even well into the process). When done correctly, the process is collaborative across business units and developers, making for a stronger product. Last, you can roll out iterations (even if just to QA and/or acceptance testing) without the big bang.
Joel is using the straw man arguments against XP. Many misinformed naysayers against XP assume that we never think about what we’re doing up front. Of course we do. This same group assumes that there is no coherent architecture for complex XP projects. Just because we’re doing agile development doesn’t mean that we just sit down and hack out code with no planning or forethought. Believe me – I’ve had lots of experience building business software, and Big Design Up Front just plain doesn’t’ work, even when it is done well (I’m fighting it yet again even as we speak). XP delivers better quality software, in shorter times, closer to the ultimate target, which has a fighting chance of actually usefulness.
Taking this topic to the logical conclusion, I wonder what would happen if a product company did a full-on agile approach? Building the product based on custom feedback from the early iterations. You would need a patient customer base, willing to comment on the work in progress. I can’t help but believe that, just as in the business software world, you would end up with a better product. How many features could you eliminate in something like Word if it had been developed incrementally? So much useless cruft could be removed from commercial software if product teams listened to their customers while developing the software rather than the complaints after it is done.
Some companies are tiptoeing in this direction. Check out JetBrains Early Access Program for innovative tools like Fabrique and MPS (The Meta Programming System). I think these products will be extraordinary if they can get their target audience to give them feedback. Agile product development – what a concept!